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Young jedi needs pcb/switch type assistance!

Discussion in 'General Electronics Discussion' started by kao, Jun 20, 2012.

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  1. kao

    kao

    7
    0
    Jun 20, 2012
    Hi,
    My son wanted help making a lightsaber, so a lightsaber we have made!
    I've bought 4 neon glow ropes to use for the beam (red, green, purple, blue), and I was thinking that, due to limited space in the hilt, and for added functionality, I would like to achieve the following;

    In some way wire 4 different colour rope lights into one power supply (takes 2 AA batteries) and either have a switch for each colour, or a single switch which will operate; 1 click - colour 1, 2nd click - colour 2, 3rd click - colour 3, 4th click - colour 4, 5th click - OFF. This should allow him to use any one colour at a time but without having to physically interchange them.

    Is this possible?

    The existing switches push once for ON-static, twice for ON-flash, and third time OFF. Can these be reused?

    Sorry if this isn't clear or complete enough to convey the project in the right way for the electronic-minded, you've probably gathered that this is new to me.
    Always willing to learn new things though so any help is hugely appreciated. This sort of thing doesn't seem to be very easy to find online!
    I can upload pictures of the existing components I have if this helps (rope lights and the power supply circuitry) I have a soldering iron and lots of determination - please help if you can! :)
     
  2. CocaCola

    CocaCola

    3,635
    5
    Apr 7, 2012
    I'm not sure about your existing switches and how they operate with the device, are they part of the original solid state driver for the rope? Nor am I sure what your 'neon' glow rope actually is... Are they EL wire, and thus using a transformer? Or a string of bulbs or LEDs in a tube? Or?

    In short, you would want a 1P4T switch, this will allow for 4 selections... It might be easier and cheaper to get a 2P4T and only use one side, or parallel both sides...

    If you provide more details of the components I'm sure we can give more information on hooking it up...
     
  3. kao

    kao

    7
    0
    Jun 20, 2012
    Thank you for your encouraging reply Cocacola :)
    This is the hilt (yet to source some polycarbonate tubing for the 'beam'...)
    [​IMG]

    and this is inside, where the batteries and circuitry will be housed
    [​IMG]

    The following pics show the glow rope circuit board, wires and connections - I have 4 sets of these battery boxes, and 4 glow ropes in different colours;

    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]

    I'm afraid my knowledge of electronics isn't good, and some things have gone right over my head, e.g the solid state driver :confused:
    What, in your opinion would be the easiest way to power the 4 colours independently from a single battery box? There's room in the hilt for additional circuitry and to fix components aside of the battery container, so this can be used up if necessary, although I should add that at some point I'd also like to add a sound switch which makes the 'beam' sound from the film! Always one to bite off more than I can chew :D
     
  4. CocaCola

    CocaCola

    3,635
    5
    Apr 7, 2012
    If someone doesn't beat me to the punch, I'll get back to this later tonight when I have more time... Can you please confirm that the highlighted area in this picture is a common trace on the board? I tried adjusting the contrast of the photo and it appears to be common, but the surface glare in the photo has left a smidgen of doubt that I want to clarify...
     

    Attached Files:

  5. CocaCola

    CocaCola

    3,635
    5
    Apr 7, 2012
    Never mind the previous question, it's cheaper (and easier to source) to just do it with a 2p4t vs a common ground and 1p4t switch that the above inquiry was for, so my question no longer applies...

    OK first and foremost, be mindful of the polarity off all the wires when doing this! I can't stress this enough, you might short out something if the make to break isn't clean in the switch if polarity is mix matched...

    What you are going to want to do is take the black wire pair that is attached to the circuit board, and mark ONE of the wires, use tape a sticker or whatever, but make sure only one wire is marked and your mark won't just fall off :p if you look at it funny...

    Now take each of the 4 EL wires and plug it into the circuit board, and mark the wire directly across from the one you just marked on the circuit board... See attached image #1

    [​IMG]

    The plug is polarized so when you plug them together it's easy to identify polarity...

    When you are done you will have marked polarity on all the units, this is important as the next step is to cut all those connectors off, so you just have wires...

    You will want to get one of these switches, this is a 10 lot on Ebay for $2.94 delivered... You will have a few extra ;)

    http://www.ebay.com/itm/SS24D02-2P4...ltDomain_0&hash=item27c7a3e046#ht_1545wt_1163

    You will likely not find these locally unless you have a very well stocked electronics supply house, thus I recommend just purchasing them and waiting for them to arrive... I'm also going to base my attachment on this particular switch, hookup might vary on another switch...

    See attachment #2 on how to hook the circuit board and the 4 EL wires to this switch, solder is HIGHLY preferable to twist and tape! Power it up and start sliding the switch up down...

    [​IMG]

    On word of caution, the solid state driver board produces upwards of 200 volts, the switch and all connections should either be heat shrink tubing after solder or wrapped in electrical tape, or even just one big blob of hot glue attached to the bottom of the switch so that no finger come in contact with exposed wires or switch pins... Also be mindful when mounting the switch, it should be mounted from the inside through a slit in the hilt (vs outside the hilt) so that the child's fingers do not find there way to touching an exposed wire...

    If you have any further question shoot away, and good luck... BTW the existing push button on the circuit board will still perform as it did originally for the additional effects...
     

    Attached Files:

    Last edited: Jun 28, 2012
  6. kao

    kao

    7
    0
    Jun 20, 2012
    Thank you so much for your advice and diagrams - I've just ordered the switches, can't wait for them to arrive to try it out :)

    Hopefully I'll have the sounds effects and tubing sorted by the time they arrive. Looking forward to the final result!
     
  7. CocaCola

    CocaCola

    3,635
    5
    Apr 7, 2012
    How much space do you have left for sound?
     
  8. kao

    kao

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    Jun 20, 2012
    The top of the hilt is a 40mm plastic coupling (standard plumbing type),and where the compartment is shown opened up in the image below, the metal washer that you see with the threaded rod coming from it can be removed - below it is hollow metal tubing.

    If the components don't fit in alongside the battery compartment and switch then I can hopefully put them below the washer in the main handgrip area. If I am correct the sound components, depending on what I use, can be run from a button cell battery which shouldn't need replacing too often?

    Have contacted some UK plastics manufacturers to enquire about suitable high-impact resistant tubing this evening. Fingers crossed I can find some at a reasonable price!
     
  9. KJ6EAD

    KJ6EAD

    1,114
    159
    Aug 13, 2011
    That switch is made for PCB mounting. Did you plan to mount it on a piece of perf or pad-per-hole prototyping board cut to fit the housing? It might be made more stable that way.
     
  10. kao

    kao

    7
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    Jun 20, 2012
    Would it be ok to use epoxy resin to hard-set the wires in place after soldering and seal the back of the switch? If so this should give excellent stability and I could fix the wires in with the same stuff to minimise any pull on the switch.
     
    Last edited: Jun 29, 2012
  11. CocaCola

    CocaCola

    3,635
    5
    Apr 7, 2012
    That is what I would do, but likely using hot glue to actually hold the wires, and epoxy to hold the switch to the hilt, I like hot glue because if repairs are needed to the wires it's a lot easier to get off then epoxy, plus it's quick ;) Mounting it to a PC board sometimes has an advantage as well, as it gives you a nice base to work from...
     
  12. kao

    kao

    7
    0
    Jun 20, 2012
    Hello again,
    Switches arrived and I wired the glow ropes in as advised - works perfectly!:D:D
    ....Then I ran into a technical hitch in the design - the battery compartment is too long for the section it needs to fit into. 'No problem' I thought - I'll use a 9v battery instead. Not only will it fit better but the connection is less likely to come loose than with 2xAAs.

    I sought some advice from a friend of a friend who said that in order to achieve this, I would need this regulator: TS2950CT-3.3 which I bought along with a 9v battery clip
    He advised that it should be soldered as follows;
    Left pin> +ve on battery clip
    middle pin>ground on battery clip plus -ve on board
    right pin> +ve on board

    This I did. Didn't work
    I found a datasheet online which indicated the left and right should be the reverse of what I did (here for reference) so I resoldered but still nothing.

    I checked the board was still ok by backtracking and hooking it up to the 2 AA batteries again and it all works fine. I'm stumped as to what I need to do next. It seems as though the 9v battery power is just not coming through at all. I tried a second battery clip and then a second regulator as I bought 2 (have 2 kids :rolleyes:). I also tried an alternative battery, althoug the first one is a rechargeable 9v which is new and had been charged overnight.
    Now that I've learned what a regulator is and what it looks like, I've noticed there is another one already on the board as visible in the pics above. Could that be causing a problem perhaps, being double-regulated?
     
    Last edited: Jul 22, 2012
  13. CocaCola

    CocaCola

    3,635
    5
    Apr 7, 2012
    The 150mA rating is likely too low for your application, you should try a 1A regulator, but I can't seem to find a fixed voltage one on Maplin... You might have to go with and adjustable one if Maplin is your only option?
     
  14. kao

    kao

    7
    0
    Jun 20, 2012
    Hi CC
    Maplin is the best option for being able to collect locally, but mail order isn't out of the question. So I'd be able to do a straight swap for a 1A regulator and in theory it *should* then work on a 9v battery? There's no danger of frazzling any components using a higher rated regulator is there?
    Your help is hugely appreciated!
     
  15. CocaCola

    CocaCola

    3,635
    5
    Apr 7, 2012
    Nope, no worries about frying anything the circuit will only draw the current it needs if you are going to mail order look for a 1.5 or 2.0 amp version (in the same TO-220 package) the extra will ensure you have enough head room, short of measuring what your circuit it is actually using... 1A might very well be enough, and in likelihood is, I'm just aiming on the side of planning for worst case and if you mail order you have the option to get a higher rated one...

    You can get a variable regular at Maplin, but you will need to use a few resistors to set the voltage level... Heck Maplin might even have a fixed one if you visit, I just hate their site and search features and being in the US don't know what the actual retail fronts look like...

    In either case get the datasheet and be mindful of the pin out, I have found that with many 3.3 Volt regulators they like to swap the standard TO-220 regulator pin out locations for whatever reason...
     
  16. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

    8,393
    1,271
    Nov 28, 2011
    Is it a good idea to switch the high-voltage path? You could switch the battery between the four inverter boards instead. That would mean four PCBs instead of just one, but might be safer and more reliable. Just asking.
     
  17. CocaCola

    CocaCola

    3,635
    5
    Apr 7, 2012
    Probably not 'ideal' but in this case it's really the most viable solution, the voltage is not huge nor does it have many milliamps behind it, so the switch should have no problems with it... And due to space constraints the easiest and most straight forward solution here as there is not much room in that hilt...
     
  18. KJ6EAD

    KJ6EAD

    1,114
    159
    Aug 13, 2011
    Could you solve the space problem by separating the AAA battery holder and inverter using a new battery holder? I don't have much confidence in a 9V battery holding up well, especially while dropping ~6V through a regulator.

    It looks like your housing has a partition of sorts. Would it be possible to fit the inverter and color selector above the partition and the batteries below?
     
    Last edited: Jul 25, 2012
  19. CocaCola

    CocaCola

    3,635
    5
    Apr 7, 2012
    A fine point, I personally shy away from 9V batteries as they are really sub-par in many applications, they just don't have the mAh that an AA or AAA will provide at the lower voltages in nearly the same space...

    BTW on that note, if you hit up the dollar store, or some cheap novelty stores, you can get these triple AAA holders that come in cheap LED flashlights... They are perfect for this application and take up about the same space as a 9V... Since you only need the 3V just jumper wire one of the battery locations and just use two batteries... You can even get fancy and make a 'fake' battery out of a section of a lag bolt or metal bar cut to size, or some other fake battery look if the jumper wire doesn't appeal...
     

    Attached Files:

  20. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

    8,393
    1,271
    Nov 28, 2011
    You might want to check that the switch is a shorting type. If it's a non-shorting switch, as it moves between positions the inverter will be working with no load. While it probably won't damage the inverter (though it may not be designed to run without a load), the voltage is bound to increase and this could cause arcing inside the switch. Even if that's not unsafe, it might be a bit disconcerting to a kid!
     
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